Three-dimensional map navigation display method

ABSTRACT

A model transforming data generating portion  4  extracts parameter data corresponding to a given road area from two-dimensional map data in a two-dimensional map data storage portion  3 . Subsequently, the model transforming data generating portion  4  reads out pattern data corresponding to the specified road area from a pattern model storage portion  5  and generates model transforming data. An image data generating portion  6  transforms a corresponding three-dimensional map display model by using the generated model transforming data to generate three-dimensional image data. The generated three-dimensional image data is given to and displayed in a display  7 . The operator operates an input portion  2  on the basis of the contents displayed in the display  7  to correct the generated model transforming data.

This is a Divisional Application of Ser. No. 09/319,864, filed Jun. 14,1999, now U.S. Pat. No. 6,411,293 B1.

TECHNICAL FIELD

The present invention relates to three-dimensional map display devices,and more particularly to a device for simply displaying athree-dimensional configuration of a target area on a map.

BACKGROUND ART

A conventional car navigation system generally navigates along the routeby displaying a two-dimensional map. In a case where a road isoverlaying on another in parallel as shown on a display navigating avicinity of freeway entrances and exits, however, a two-dimensional mapwithout a longitudinal representation often puzzles a driver as to whichway to go. Also, as to a multi-level intersection of a ordinary-typeroad to be navigated, when the display navigates to turn right afterpassing the multi-level intersection, it is difficult for the driver toinstantaneously understand the navigated route as a conventional carnavigation system does not represent the route stereoscopically.

Recently, various car navigation systems are being developed to displaya map in a three-dimensional manner. Conventionally, when a map isthree-dimensionally displayed, width and height information is manuallyprovided to data about roads on a two-dimensional map in advance so asto generate three-dimensional polygon data from the map data having theinformation provided, and then the three-dimensional polygon data isstored in a map storage medium (CD-ROM, DVD, etc.). When a vehiclereaches a point to be navigated, a car navigation system in which thismap storage medium is provided reads out corresponding three-dimensionalpolygon data from the map storage medium and displays athree-dimensional image.

The conventional system, however, requires width and height informationto be added to every piece of road data on a two-dimensional map, whichconsiderably complicates the processing. Further, it requirespreparation such as measurements, and the like. Moreover, sincetwo-dimensional map data contains a large amount of information which donot conform to the real-world road locations, an accuracy of athree-dimensional map obtained through such data on the two-dimensionalmap data is poor, which confuses the driver more. Information on roadlocations on a two-dimensional map may be corrected or configurationdata on a completed three-dimensional map may be corrected with a CADtool, and the like in order to obtain a desired three-dimensional map.It will require a large number of addition processing steps. Further,since an accuracy of the conventional polygon automatic generatingalgorithm is poor, parts separated into small links andcoupling/branching parts between two road links differing in widthcannot be smoothly connected. That is to say, the polygon data does notcoincide with the real-world road configuration, resulting in areduction of the safety.

Moreover, in the conventional system, the three-dimensional polygon dataitself is stored in a map storage medium (CD-ROM, DVD, etc.), andtherefore the amount of map data to be stored is too large tothree-dimensionally display many areas. To solve such an inconvenience,two-dimensional map data containing added width and height informationmay be stored in the map storage medium, in which case a car navigationsystem carried on a vehicle creates the three-dimensional polygon data.However, this method largely increases the load on a CPU of the carnavigation system, resulting in another problem that the map cannot bescrolled at high speed.

Accordingly, an object of the present invention is to provide athree-dimensional map display method and a device which can easily andsimply display the three-dimensional configuration of target areas on amap, with a largely reduced amount of data stored in a storage medium,and a device for creating data used in the method and device.

DISCLOSURE OF THE INVENTION

The present invention has the following features to achieve the objectmentioned above.

A first aspect of the invention is directed to a device for creatingmodel transforming data used to transform a three-dimensional mapdisplay model, wherein a three-dimensional configuration of a given parton a map is classified in advance into a plurality of patterns and astandard three-dimensional map display model is prepared for eachpattern, and the model transforming data creating device comprises:

a two-dimensional map data storage portion for storing two-dimensionalmap data;

a parameter data extracting portion for extracting parameter datacorresponding to the given part from the two-dimensional map data storedin the two-dimensional map data storage portion;

a parameter data analyzing portion for analyzing the parameter dataextracted by the parameter data extracting portion to generate the modeltransforming data; and

a storage portion for storing the model transforming data generated bythe parameter data analyzing portion.

As stated above, according to the first aspect, instead of thethree-dimensional image data itself, the model transforming data fortransforming a previously prepared three-dimensional map display modelinto a desired form is generated as data for obtaining athree-dimensional image of a given part on a map, and then the data forthree-dimensional map display can be provided in an extremely compressedform as compared with conventional ones.

According to a second aspect which depends on the first aspect,

the model transforming data creating device further comprises a patternmodel storage portion for storing pattern data defining sorts ofparameters required when transforming the three-dimensional map displaymodel for each pattern,

wherein the parameter data analyzing portion comprises:

a pattern data reading portion for reading the pattern datacorresponding to the given part from the pattern model storage portion;and

a data converting portion for converting the parameter data extracted bythe parameter data extracting portion into the model transforming dataon the basis of the pattern data read out by the pattern data readingportion.

As stated above, according to the second aspect, the parameter data isconverted into the model transforming data on the basis of the patterndata, and more detailed model transforming data can be created ascompared with the case in which the model transforming data is createdfrom only the parameter data.

According to a third aspect which depends on the second aspect,

the pattern data reading portion comprises a pattern determining portionfor determining the pattern on the basis of the parameter data extractedby the parameter data extracting portion and reading out the patterndata corresponding to the determined pattern from the pattern modelstorage portion.

As stated above, according to the third aspect, the parameter data canbe automatically read from the parameter data storage portion withoutrequiring manual operation.

According to a fourth aspect which depends on the third aspect,

the pattern determining portion comprises:

a branching part road attribute deciding portion for deciding attributesof roads around a branching point on the basis of the parameter dataextracted by the parameter data extracting portion; and

a branch type deciding portion for deciding the type of the branching onthe basis of the road attributes decided by the branching part roadattribute deciding portion to determine the pattern.

As stated above, according to the fourth aspect, the pattern isdetermined according to the road attributes at a branching pointespecially requiring three-dimensional display, which enables patterndiscrimination more conforming with the real-world road configuration.

According to a fifth aspect which depends on the fourth aspect,

the parameter data analyzing portion further comprises:

a parameter data classifying portion for classifying the parameter dataaccording to road function on the basis of the pattern determined by thepattern determining portion; and

a data integrating portion for integrating the parameter data classifiedby the parameter data classifying portion within each classified group,and

the data converting portion converts the parameter data integrated bythe data integrating portion into the model transforming data.

As stated above, according to the fifth aspect, not the mere parameterdata extracted from the two-dimensional map data but the integratedparameter data is converted into the model transforming data, so that athree-dimensional map display model with a less number of connectedportions can be adopted to provide a beautiful three-dimensional image,and the finally obtained three-dimensional image can be simplified onthe basis of the road function to provide navigation display easy tounderstand for the user.

According to a sixth aspect which depends on the fifth aspect,

the parameter data classifying portion comprises:

a link tracing portion for tracing a desired link on the basis of thetwo-dimensional parameter data extracted by the two-dimensionalparameter data extracting portion and temporarily storing and holdingdata of the traced link; and

a link data classifying portion for classifying the link data stored andheld in the link tracing portion on the basis of the pattern determinedby the pattern determining portion.

As stated above, according to the sixth aspect, the amount of parameterdata as the source data for classification can be reduced depending onthe condition for tracing links, and then the classifying operation canbe performed at high speed.

According to a seventh aspect which depends on the second aspect,

the pattern data reading portion reads the pattern data corresponding toa pattern indicated by an operator from the pattern data storageportion.

According to an eighth aspect which depends on the second aspect,

the data converting portion obtains values of part of the parametersdefined by the pattern data read by the pattern data reading portiondirectly from the parameter data extracted by the parameter dataextracting portion and obtains remaining parameter values by inferenceprocessing.

As stated above, according to the eighth aspect, parameters wanting whengenerating the model transforming data can be automatically obtained byinference.

According to a ninth aspect which depends on the second aspect,

the data converting portion obtains values of part of the parametersdefined by the pattern data read by the pattern data reading portiondirectly from the parameter data extracted by the parameter dataextracting portion and obtains remaining parameter values through aninstruction from an operator.

According to a tenth aspect which depends on the first aspect,

the model transforming data creating device further comprises:

an image data generating portion for generating three-dimensional imagedata by applying the model transforming data generated by the parameterdata analyzing portion to the corresponding three-dimensional mapdisplay model and transforming the three-dimensional map display model;and

a display portion for displaying the three-dimensional configuration ofthe given part on the basis of the three-dimensional image datagenerated by the image data generating portion.

As stated above, according to the tenth aspect, since thethree-dimensional configuration obtained on the basis of the generatedmodel transforming data is displayed in a real-time manner, it is easyto see whether desired model transforming data has been obtained.

According to an eleventh aspect which depends on the tenth aspect,

the model transforming data creating device further comprises a modeltransforming data correcting portion for correcting the modeltransforming data generated by the parameter data analyzing portion inresponse to an instruction from an operator.

As stated above, according to the eleventh aspect, the modeltransforming data can be corrected and the corrected three-dimensionalconfiguration can be displayed, and thus the correcting operation can beachieved easily.

According to a twelfth aspect which depends on the first aspect,

the parameter data extracting portion extracts the parameter data of apart indicated by an operator from the two-dimensional map data.

According to a thirteenth aspect which depends on the first aspect,

the parameter data extracting portion extracts the parameter data of apart which conforms with a previously set condition from thetwo-dimensional map data.

As stated above, according to the thirteenth aspect, the part to bethree-dimensionally displayed on a map can be automatically specified toextract parameters.

According to a fourteenth aspect, a device for creatingthree-dimensional polygon data used to display a three-dimensionalconfiguration of a given part on a map comprises:

a two-dimensional map data storage portion for storing two-dimensionalmap data;

a parameter data extracting portion for extracting parameter datacorresponding to the given part from the two-dimensional map data storedin the two-dimensional map data storage portion;

a parameter data analyzing portion for analyzing the parameter dataextracted by the parameter data extracting portion to generate modeltransforming data;

a three-dimensional polygon data generating portion for generating thethree-dimensional polygon data by applying the model transforming datagenerated by the parameter data analyzing portion to a correspondingthree-dimensional map display model to transform the three-dimensionalmap display model; and

a three-dimensional polygon data storage portion for storing thethree-dimensional polygon data generated by the three-dimensionalpolygon data generating portion.

As stated above, according to the fourteenth aspect, thethree-dimensional polygon data is obtained by transforming a previouslyprepared three-dimensional map display model, so that the computationfor generating the three-dimensional polygon data can be simplified.

According to a fifteenth aspect, a device for creating three-dimensionalimage data used to display a three-dimensional configuration of a givenpart on a map comprises:

a two-dimensional map data storage portion for storing two-dimensionalmap data;

a parameter data extracting portion for extracting parameter datacorresponding to the given part from the two-dimensional map data storedin the two-dimensional map data storage portion;

a parameter data analyzing portion for analyzing the parameter dataextracted by the parameter data extracting portion to generate modeltransforming data;

a three-dimensional polygon data generating portion for generatingthree-dimensional polygon data by applying the model transforming datagenerated by the parameter data analyzing portion to a correspondingthree-dimensional map display model to transform the three-dimensionalmap display model;

a three-dimensional image data generating portion for generating thethree-dimensional image data on the basis of the three-dimensionalpolygon data generated by the three-dimensional polygon data generatingportion; and

a three-dimensional image data storage portion for storing thethree-dimensional image data generated by the three-dimensional imagedata generating portion.

As stated above, according to the fifteenth aspect, thethree-dimensional image data is generated from the three-dimensionalpolygon data obtained by transforming a previously preparedthree-dimensional map display model, so that the computation forgenerating the three-dimensional image data can be simplified.

A sixteenth aspect is direct to a three-dimensional map display devicefor displaying a three-dimensional configuration of a given part on amap,

wherein the three-dimensional configuration of the given part on the mapis classified in advance into a plurality of pattern and a standardthree-dimensional map display model is prepared for each pattern, andthe three-dimensional map display device comprises:

a two-dimensional map data storage portion for storing two-dimensionalmap data;

a parameter data extracting portion for extracting parameter datacorresponding to the given part from the two-dimensional map data storedin the two-dimensional map data storage portion;

a parameter data analyzing portion for analyzing the parameter dataextracted by the parameter data extracting portion to generate modeltransforming data used to transform the three-dimensional map displaymodel;

an image data generating portion for generating three-dimensional imagedata by applying the model transforming data generated by the parameterdata analyzing portion to the corresponding three-dimensional mapdisplay model to transform the three-dimensional map display model intoa desired form; and

a display portion for displaying the three-dimensional configuration ofthe given part on the basis of the three-dimensional image datagenerated by the image data generating portion.

As stated above, according to the sixteenth aspect, the mapconfiguration is classified into a plurality of patterns and a standardthree-dimensional map display model prepared for each pattern istransformed to obtain a three-dimensional image, which enablesthree-dimensional display more fitted to the object of the navigation(that is to say, to enable clear understanding of the correspondencebetween real-world roads and navigated routes) as compared with theconventional system in which a three-dimensional image is obtaineddirectly from two-dimensional map data with added width and heightinformation. That is to say, according to the sixteenth aspect, thebasic configuration of roads is previously prepared in the form of athree-dimensional map display model, and therefore the relation amongroads, such as how roads are connected to one another or branched, isnot largely changed even when the three-dimensional map display model islargely transformed. Accordingly, errors in some degrees existing on thetwo-dimensional map data are automatically corrected at the time whenthe pattern of the specified road part is determined, which reduces apossibility of displaying errors far apart from the original object ofthe navigation. Also, according to the sixteenth aspect, it is notnecessary to perform all the steps for calculating and generating thethree-dimensional image data, but it can be generated by just performingthe calculation of transforming a previously defined three-dimensionalmap display model on the basis of the model transforming data, and theamount of calculation can be largely reduced as compared withconventional case. This enables high-speed picture drawing processing.Further, according to the sixteenth aspect, since the model transformingdata is generated within the three-dimensional map display device, themap storage medium can be used to store the two-dimensional map dataonly, and the device can work with almost the same amount of previouslystored map data as a conventional map display device displaying atwo-dimensional map.

According to a seventeenth aspect which depends on the sixteenth aspect,

the three-dimensional map display device further comprises a patternmodel storage portion for storing pattern data defining sorts ofparameters required when transforming the three-dimensional map displaymodel for each pattern, and

the parameter data analyzing portion comprises:

a pattern data reading portion for reading out the pattern datacorresponding to the given part from the pattern model storage portion;and

a data converting portion for converting the parameter data extracted bythe parameter data extracting portion into the model transforming dataon the basis of the pattern data read by the pattern data readingportion.

As stated above, according to the seventeenth aspect, the parameter datais converted into the model transforming data on the basis of thepattern data, and more detailed model transforming data can thus becreated as compared with a case in which the model transforming data iscreated from only the parameter data.

According to an eighteenth aspect which depends on the seventeenthaspect,

the pattern data reading portion comprises a pattern determining portionfor determining the pattern on the basis of the parameter data extractedby the parameter data extracting portion and reading out the patterndata corresponding to the determined pattern from the pattern modelstorage portion.

As stated above, according to the eighteenth aspect, the parameter datacan be automatically read out from the parameter data storage portionwithout through manual operation.

According to a nineteenth aspect which depends on the eighteenth aspect,

the pattern determining portion comprises:

a branching part road attribute deciding portion for deciding attributesof roads around a branching point on the basis of the parameter dataextracted by the parameter data extracting portion; and

a branch type deciding portion for deciding the type of the branching onthe basis of the road attributes decided by the branching part roadattribute deciding portion to determine the pattern.

As stated above, according to the nineteenth aspect, the pattern isdetermined in accordance with road attributes at a branching pointespecially requiring three-dimensional display, so that the pattern canbe determined in a manner more fitted to the real-world roadconfiguration.

According to a twentieth aspect which depends on the nineteenth aspect,

the parameter data analyzing portion further comprises:

a parameter data classifying portion for classifying the parameter dataaccording to road function on the basis of the pattern determined by thepattern determining portion; and

a data integrating portion for integrating the parameter data classifiedby the parameter data classifying portion within each classified group;and

the data converting portion converts the parameter data integrated bythe data integrating portion into the model transforming data.

As stated above, according to the twentieth aspect, not the mereparameter data extracted from the two-dimensional map data but theintegrated parameter data is converted into the model transforming data,so that a three-dimensional map display model with a less number ofconnected portions can be adopted to provide a beautifulthree-dimensional image, and the finally obtained three-dimensionalimage can be simplified on the basis of road function to providenavigation display easy to understand for the user.

According to a twenty-first aspect which depends on the twentiethaspect,

the parameter data classifying portion comprises:

a link tracing portion for tracing a desired link on the basis of thetwo-dimensional parameter data extracted by the two-dimensionalparameter data extracting portion and temporarily storing and holdingdata of the traced link; and

a link data classifying portion for classifying the link data stored andheld in the link tracing portion on the basis of the pattern determinedby the pattern determining portion.

As stated above, according to the twenty-first aspect, the amount of theparameter data as the source data for classification can be reduceddepending on the condition used when tracing links, and the computationfor classification can be performed at high speed.

According to a twenty-second aspect which depends on the seventeenthaspect,

the data converting portion obtains values of part of the parametersdefined by the pattern data read by the pattern data reading portiondirectly from the parameter data extracted by the parameter dataextracting portion and obtains remaining parameter values by inference.

As stated above, according to the twenty-second aspect, parameterswanting in generating the model transforming data can be automaticallyobtained by inference.

According to a twenty-third aspect which depends on the twenty-secondaspect,

the three-dimensional map display device is installed in a carnavigation device for navigating a vehicle on the map.

A twenty-fourth aspect is directed to a three-dimensional map displaydevice for displaying a three-dimensional configuration of a given parton a map,

wherein the three-dimensional configuration of the given part on the mapis classified in advance into a plurality of patterns and a standardthree-dimensional map display model is prepared for each pattern, andthe three-dimensional map display device comprises:

a model transforming data storage portion for storing model transformingdata for transforming the three-dimensional map display model;

an image data generating portion for generating three-dimensional imagedata by reading out the model transforming data corresponding to thegiven part and applying the model transforming data to the correspondingthree-dimensional map display model to transform the three-dimensionalmap display model into a desired form; and

a display portion for displaying the three-dimensional configuration ofthe given part on the basis of the three-dimensional image datagenerated by the image data generating portion.

As stated above, according to the twenty-fourth aspect, the mapconfiguration is classified into a plurality of patterns and a standardthree-dimensional map display model prepared for each pattern istransformed to obtain a three-dimensional image, which enablesthree-dimensional display more fitted to the object of the navigation(that is to say, to understand a correspondence between real-world roadsand navigated routes in a clear manner) as compared with theconventional system in which a three-dimensional image is obtaineddirectly from two-dimensional map data with added width and heightinformation. That is to say, according to the twenty-fourth aspect, thebasic configuration of roads is previously prepared as athree-dimensional map display model, and therefore the relation amongroads, such as how roads are connected to one another or branched, isnot largely changed even when the three-dimensional map display model islargely transformed. Accordingly, errors in some degrees existing on thetwo-dimensional map data are automatically corrected at the time whenthe pattern of the specified road part is determined, which reduces aprobability of displaying errors far apart from the original object ofthe navigation. Also, according to the twenty-fourth aspect, it is notnecessary to perform all the steps for calculating and generating thethree-dimensional image data, but it can be generated by just performingthe calculation of transforming a previously defined three-dimensionalmap display model on the basis of the model transforming data, and theamount of calculation can be largely reduced as compared with aconventional case. This enables high-speed picture drawing processing.Further, according to the twenty-fourth aspect, the device stores themodel transforming data extremely compressed as compared with thethree-dimensional polygon data and three-dimensional image data, so thatthe amount of previously stored map data (data required to display athree-dimensional map) can be considerably reduced, as compared with aconventional map display device displaying a three-dimensional map.

According to a twenty-fifth aspect which depends on the twenty-fourthaspect,

the three-dimensional map display device is installed in a carnavigation device for navigating a vehicle on the map.

A twenty-sixth aspect is directed to a method for displaying athree-dimensional configuration of a given part on two-dimensional mapdata, the method comprising the steps of:

classifying in advance the three-dimensional configuration of the givenpart into a plurality of patterns and preparing in advance a standardthree-dimensional map display model for each pattern;

extracting parameter data corresponding to the given part from thetwo-dimensional map data;

generating model transforming data from the extracted parameter data;and

applying the model transforming data to the correspondingthree-dimensional map display model to transform the three-dimensionalmap display model into a desired form, thereby obtaining athree-dimensional image of the given part.

As stated above, according to the twenty-sixth aspect, the mapconfiguration is classified into a plurality of patterns and a standardthree-dimensional map display model prepared for each pattern istransformed to obtain a three-dimensional image, which enablesthree-dimensional display more fitted to the object of the navigation(that is to say, to understand a correspondence between real-world roadsand navigated roads in a clear manner) as compared with the conventionalsystem in which a three-dimensional image is obtained directly fromtwo-dimensional map data with added width and height information. Thatis to say, according to the twenty-sixth aspect, the basic configurationof roads is previously prepared as a three-dimensional map display modeland therefore the relation among roads, such as the configuration ofconnections and branches of roads, is not largely changed even when thethree-dimensional map display model is largely transformed. Accordingly,errors in some degrees existing on the two-dimensional map data areautomatically corrected at the time when the pattern of the specifiedroad part is determined, which reduces a possibility of displayingerrors far apart from the original object of the navigation. Also,according to the twenty-sixth aspect, it is not necessary to perform allthe steps for calculating and generating the three-dimensional imagedata, but it can be generated by just performing the calculation oftransforming a previously defined three-dimensional map display model onthe basis of the model transforming data, and the amount of calculationcan be largely reduced as compared with conventional devices. Thisenables high-speed picture drawing processing.

A twenty-seventh aspect is directed to a storage medium used in athree-dimensional map display device in which a three-dimensionalconfiguration of a given part on two-dimensional map data is classifiedin advance into a plurality of patterns and a standard three-dimensionalmap display model is prepared in advance for each pattern, and thethree-dimensional map display model is transformed into a desired formto generate and display three-dimensional image data of the given part,

wherein the storage medium contains model transforming data fortransforming the three-dimensional map display model into the desiredform in correspondence with each road part to be three-dimensionallydisplayed.

As stated above, according to the twenty-seventh aspect, data forthree-dimensional map display can be stored in an extremely compressedform.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the structure of a model transformingdata creating device according to an embodiment of the presentinvention.

FIG. 2 is a block diagram showing the more detailed structure of themodel transforming data generating portion 4 shown in FIG. 1.

FIG. 3 is a block diagram showing the more detailed structure of theparameter data analyzing portion 43 shown in FIG. 2.

FIG. 4 is a flowchart used to explain the operation of the modeltransforming data creating device 1 shown in FIG. 1.

FIG. 5 is a diagram showing an example of two-dimensional parameter dataextracted from two-dimensional map data.

FIG. 6 is a diagram showing the map parameters of FIG. 5 in a formvisualized as a two-dimensional map.

FIG. 7 is a flowchart showing the more detailed operation of thesubroutine step S5 shown in FIG. 4.

FIG. 8 is a diagram showing examples of types of branching roads.

FIG. 9 is a diagram showing an example of three-dimensional map displaymodel pattern used in the case in which a road on the ground branchesout into an elevated road and a side pass.

FIG. 10 is a diagram showing an example of three-dimensional map displaymodel pattern used in the case in which a road on the ground branchesout into an underpass and a side pass.

FIG. 11 is a diagram showing an example of three-dimensional map displaymodel pattern used in the case in which an elevated road branches outinto an elevated road and a side pass.

FIG. 12 is a diagram showing an example of pattern data stored in thepattern model storage portion 5 of FIG. 1.

FIG. 13 is a diagram showing an example of parameter data classifiedaccording to road function.

FIG. 14 is a flowchart showing the more detailed operation of thesubroutine step S6 shown in FIG. 4.

FIG. 15 is a diagram showing an example of a two-dimensional map.

FIG. 16 is a diagram showing an example of results obtained by tracinglinks.

FIG. 17 is a diagram showing an example of results obtained by storingthe link data of the traced links.

FIG. 18 is a diagram showing an example of results obtained byclassifying the links according to road function.

FIG. 19 is a diagram showing an example of parameter data generated byintegrating the classified data.

FIG. 20 is a diagram showing the parameter data of FIG. 19 visualized asa two-dimensional map.

FIG. 21 is a diagram showing an example of pattern data in whichparameters are set (model transforming data).

FIG. 22 is a diagram showing examples of shapes of roads which belong toa first category.

FIG. 23 is a diagram showing examples of shapes of roads which belong toa second category.

FIG. 24 is a diagram showing examples of shapes of roads which belong toa third category.

FIG. 25 is a diagram showing an example of display of athree-dimensional map generated by using the model transforming datashown in FIG. 21.

FIG. 26 is a block diagram showing the more detailed structure of theimage data generating portion 6 shown in FIG. 1.

FIG. 27 is a block diagram showing the more detailed structure of thethree-dimensional polygon data generating portion 61 shown in FIG. 26.

FIG. 28 is a diagram showing an example of contents of parameters anddefault values thereof stored in the configuration attribute storageportion 613 of FIG. 27.

FIG. 29 is a flowchart showing the operation of the three-dimensionalpolygon data generating portion 61 shown in FIG. 26.

FIG. 30 is a schematic diagram used to explain the operation of themodel transforming data analyzing portion 611 shown in FIG. 27.

FIG. 31 is a schematic diagram used to explain the operation of thethree-dimensional polygon data synthesizing portion 612 shown in FIG.27.

FIG. 32 is a diagram showing the outline of the processing of functionFUNC1.

FIG. 33 is an image diagram showing three-dimensional polygon datagenerated by the function FUNC1.

FIG. 34 is a diagram showing the outline of the processing of functionFUNCB1.

FIG. 35 is a diagram showing an example of results obtained by theprocessing of the function FUNCB1.

FIG. 36 is an image diagram showing three-dimensional polygon datagenerated by the function FUNCB1.

FIG. 37 is a block diagram showing the structure of a navigation deviceaccording to an embodiment of the present invention.

FIG. 38 is a block diagram showing the greater details of the structureof the navigating portion 14 shown in FIG. 37.

FIG. 39 is a flowchart showing the operation of the navigating portion14 shown in FIG. 37.

FIG. 40 is a block diagram showing the greater details of the structureof the three-dimensional map display portion 143 shown in FIG. 38.

FIG. 41 is a flowchart showing the operation of the three-dimensionalmap display portion 143 shown in FIG. 40.

FIG. 42 is a block diagram showing the structure of a three-dimensionalmap display portion 143 having a communication device.

FIG. 43 is a block diagram showing another structure of thethree-dimensional map display portion 143 shown in FIG. 38.

BEST MODE FOR CARRYING OUT THE INVENTION

Before describing embodiments of the present invention in detail, thebasic idea of the present invention will now be described to facilitateunderstanding of the invention.

The present invention was made to enable three-dimensional display of agiven road area on a map. As is well known for a conventional carnavigation system of a general type, when a navigated route comes closerto a junction or a point to turn right or left, configurations of roadsaround the point are displayed in an enlarged manner. A typicalapplication of the present invention is to three-dimensionally displaythe enlarged configurations. The present invention is also applicable toa system in which navigated roads are all three-dimensionally displayed.

In the present invention, configuration of roads to bethree-dimensionally displayed are previously classified into somepatterns each including similar types. For example, configurations ofroads are classified into a multi-level intersection, underpass,junction, elevated road, freeway, and the like. The present inventionpreviously prepares a standard three-dimensional map display model foreach of the classified patterns, and creates model transforming datafrom parameters extracted from two-dimensional map data and transformsthe corresponding three-dimensional map display model into desired formby applying the model transforming data. Thus, a three-dimensional imagecorresponding to the given road area is obtained.

Since a conventional system obtains a three-dimensional image byhandling two-dimensional map data containing additional width and heightinformation as three-dimensional coordinate data, it completely neglectshow the roads are connected to one another or branched. Accordingly,when the two-dimensional map data contains errors, the errors aredirectly incorporated into the three-dimensional image. For example anelevated road may be discontinued halfway or branched roads running inparallel may be largely curved.

On the other hand, the present invention previously classifies roadconfigurations into a plurality of patterns, prepares a standardthree-dimensional map display model for the individual patterns, andtransforms the three-dimensional map display models to obtainthree-dimensional images, which enables three-dimensional display morefitted to the original object of the car navigation (that is to say, tounderstand a correspondence between real-world roads and a navigatedroute in a clear manner) as compared with the conventional system inwhich three-dimensional image is obtained directly from two-dimensionalmap data having width and height information added. That is, in thepresent invention, basic configurations of roads are previously preparedin the form of three-dimensional map display models in athree-dimensional image data generating algorithm, and therefore basicrelation among roads, i. e., how the roads are connected to one anotheror branched, is not largely changed even when the three-dimensional mapdisplay models are largely transformed. Accordingly, errors in somedegrees existing on the two-dimensional map data are automaticallycorrected when a configuration of a road to be three-dimensionallydisplayed is determined to which pattern it belongs, which reduces aprobability of displaying errors far apart from the original object ofthe navigation system.

On the other hand, since the present invention three-dimensionallydisplays the map configuration in deformed (simplified or exaggerated)manner, the displayed three-dimensional image does not completelyconform with the real-world road configuration, unlike the conventionalsystem in which two-dimensional map data having width and heightinformation added is handled as three-dimensional coordinate data. Inother words, as compared with the conventional system, the presentinvention displays a three-dimensional map in a form closer to animatedcartoon. However, when a vehicle is navigated, it is not necessary thatthe displayed three-dimensional map completely corresponds to thereal-world road configuration. In car-navigation, no problem arises evenif the angles of slopes of elevated roads and scales of roads differfrom the actual values. The object of the car-navigation can be achievedif the display can show whether roads are rising or descending and howmany lanes they have, at least. That is to say, the object ofcar-navigation can be achieved if the display shows enough informationfor a driver to clearly understand the correspondence between real-worldroads and the displayed navigation, such as the configuration ofbranching roads, vertical relation between roads. Accordingly, justtransforming a previously prepared three-dimensional map display modelcan sufficiently achieve the object of the car-navigation. Conversely,such deformed display as is made in the present invention is easier forthe driver to understand.

As stated above, it is not necessary to accurately transform preparedthree-dimensional map display models so as to completely correspond tothe real-world road configuration, and the object of the navigation canbe achieved by transforming the three-dimensional map display models tosuch an extent that the object of the car-navigation is not impeded.This means that the number of parameters given to the three-dimensionalmap display models can be reduced. Further, when the present inventionis applied to a car navigation system, not the three-dimensional imagedata itself but only the model transforming data for transforming thethree-dimensional map display models is stored in the map storage mediumprovided in the car navigation system with respect to the road area tobe three-dimensionally displayed. That is to say, data forthree-dimensional display can be stored in a highly compressed form inthe map storage medium, resulted in an extremely reduced amount of data.Further, when only the two-dimensional map data is stored in the mapstorage medium and the car navigation system generates modeltransforming data on the basis of the two-dimensional map data, theamount of data additionally stored in the map storage medium can bealmost zero.

Moreover, the present invention can considerably simplify a structurefor processing in the algorithm for generating the three-dimensionalimage data on the basis of model transforming data (hereinafter referredto as a three-dimensional image data generating algorithm). This isbecause the three-dimensional image data generating algorithm does nothave to perform all the steps for calculating and generatingthree-dimensional image data, but it performs only the computation fortransforming the previously defined three-dimensional map displaymodels.

It is noted that the basic idea was described above only to facilitateunderstanding of the present invention, and it should not be used toimproperly limit the scope of the invention.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

FIG. 1 is a block diagram showing the structure of a model transformingdata creating device of an embodiment of the present invention. In FIG.1, the model transforming data creating device 1 of this embodimentincludes an input portion 2, a two-dimensional map data storage portion3, a model transforming data generating portion 4, a pattern modelstorage portion 5, an image data generating portion 6, a display 7, anda model transforming data storage portion 8.

The input portion 2 includes a cross-shaped pad, a mouse, a keyboard,and the like, which is operated by an operator to enter the map number,information for specifying a road area to be three-dimensionallydisplayed, data for correcting parameters, pattern number of a patternmodel, and the like. The two-dimensional map data storage portion 3 iscomposed of a large-capacity storage device containing a storage mediumsuch as a CD-ROM or DVD, which is used to store two-dimensional mapdata. The model transforming data generating portion 4 generates modeltransforming data required when transforming the three-dimensional mapdisplay model on the basis of information entered from the input portion2, two-dimensional map data read out from the two-dimensional map datastorage portion 3, and pattern data read out from the pattern modelstorage portion 5. The pattern model storage portion 5 contains patterndata defining sorts of parameters required when transforming eachthree-dimensional map display model. The image data generating portion 6contains a three-dimensional image data generating algorithm, whichgenerates three-dimensional image data on the basis of the modeltransforming data generated in the model transforming data generatingportion 4. The display 7 displays three-dimensional configuration of aspecified road area on the basis of the three-dimensional image datagenerated in the image data generating portion 6. The model transformingdata storage portion 8 is used to store model transforming datagenerated in the model transforming data generating portion 4.

FIG. 2 is a block diagram showing the details of the structure of themodel transforming data generating portion 4 shown in FIG. 1. In FIG. 2,the model transforming data generating portion 4 includes atwo-dimensional map data reading portion 41, a parameter data extractingportion 42, and a parameter data analyzing portion 43.

The two-dimensional map data reading portion 41 reads two-dimensionalmap data for an area corresponding to a map number entered from theinput portion 2 from the two-dimensional map data storage portion 3. Theparameter data extracting portion 42 extracts parameter data indicatingattributes of each link from the two-dimensional map data read by thetwo-dimensional map data reading portion 41. The parameter dataanalyzing portion 43 analyzes the parameter data extracted by theparameter data extracting portion 42 and reads required pattern datafrom the pattern model storage portion 5 and generates the modeltransforming data for transforming the three-dimensional map displaymodel.

The model transforming data generated in the parameter data analyzingportion 43 is given to the image data generating portion 6 and convertedinto three-dimensional image data, and the display 7 displays thecorresponding three-dimensional configuration. The operator checks thecontents displayed on the display 7 to see whether a correctthree-dimensional image is displayed. When the three-dimensional imageis to be corrected, parameters for change or addition are entered fromthe input portion 2. This changes the contents of the model transformingdata generated in the parameter data analyzing portion 43 and thedisplayed contents on the display 7 change accordingly. When thethree-dimensional image displayed on the display 7 has been changed tothe form desired by the operator, the model transforming data generatedin the parameter data analyzing portion 43 is stored in the modeltransforming data storage portion 8.

FIG. 3 is a block diagram showing the greater details of the structureof the parameter data analyzing portion 43 shown in FIG. 2. In FIG. 3,the parameter data analyzing portion 43 includes a pattern determiningportion 431, a parameter data classifying portion 432, a dataintegrating portion 433, and a data converting portion 434.

The pattern determining portion 431 determines a pattern of roadconfiguration to be adopted, on the basis of the parameter data on theroad area extracted by the parameter data extracting portion 42. Theparameter data classifying portion 432 classifies the parameter data ofeach road area on the basis of the pattern determined by the patterndetermining portion 431, in accordance with characteristic parts of theintersection pattern, such as elevated road, side pass, etc. The dataintegrating portion 433 integrates the parameter data classifiedaccording to the road function by the parameter data classifying portion432 for each road function to generate normalized parameter data. Theparameter data classifying portion 432 and the data integrating portion433 form a normalizing portion 430 for normalizing the parameter data.The data converting portion 434 converts the normalized parameter dataoutputted from the data integrating portion 433 into model transformingdata on the basis of the pattern data read out from the pattern modelstorage portion 5.

For more details of the structure of the pattern determining portion431, the pattern determining portion 431 includes a branching area roadattribute deciding portion 4311 and a branch type deciding portion 4312.The branching area road attribute deciding portion 4311 decidesattributes of all roads connected to a branching point on the basis ofthe parameter data extracted by the parameter data extracting portion42. The attribute of roads represents the height of the roads from theground, which shows the configuration of the object road, i.e., elevatedroad, underpass, or a road on the ground. The branch type decidingportion 4312 detects a combination of the attributes of the roadsconnected to the branching point on the basis of the attributes of theroads decided by the branching area road attribute deciding portion 4311to determine the type of the branching. The branch type deciding portion4312 then decides a pattern of the three-dimensional map display modelto be used from the determined type of the branching and outputs acorresponding pattern number.

For the details of the structure of the parameter data classifyingportion 432, the parameter data classifying portion 432 includes a linktracing portion 4321 and a link data classifying portion 4322. The linktracing portion 4321 traces a two-dimensional map network on the basisof the parameter data extracted by the parameter data extracting portion42. When tracing the map network, link data of the three-dimensionedarea is stored by utilizing the attribute, type, angle, area, and thelike in the map data as criteria. The link data classifying portion 4322classifies the link data stored in the link tracing portion 4321 foreach road area and associates each part of the three-dimensional mapdisplay model and the two-dimensional map network.

FIG. 4 is a flowchart showing the entire operation of the modeltransforming data creating device 1 shown in FIGS. 1 to 3. Referring toFIG. 4, the operation of the model transforming data creating device 1will now be described.

First, a map number including a road area to be three-dimensionallydisplayed is entered to the model transforming data generating portion 4from the input portion 2 (step S1). This embodiment adopts DRMA (DigitalRoad Map) for a format of the two-dimensional map data stored in thetwo-dimensional map data storage portion 3. In the DRMA, a map of thewhole country is divided into a plurality of areas according to a givenunit (e.g., secondary mesh unit). The two-dimensional map data readingportion 41 in the model transforming data generating portion 4 reads outthe two-dimensional map data for an area corresponding to the map numberentered from the input portion 2, from the two-dimensional map datastorage portion 3 (step S2).

Next, the model transforming data generating portion 4 specifies a roadarea (e.g., a multi-level intersection) to be three-dimensionallydisplayed from the two-dimensional map data read out from thetwo-dimensional map data storage portion 3 (step S3). The operation ofspecifying the road area may be performed on the basis of specifyingdata entered from the input portion 2 (the former case) or may beperformed according to an algorithm for automatically specifying theroad area (the latter case). In the former case, the image datagenerating portion 6 creates image data on the two-dimensional mapcorresponding to the two-dimensional map data read out from thetwo-dimensional map data storage portion 3 and displays it on thedisplay 7. The operator draws a box, for example, around a part to bedisplayed in a three-dimensional manner on the two-dimensional map (orenlarged map thereof) displayed on the display 7 so as to specify a roadarea. At this time, the input portion 2 outputs specifying dataindicating the road area specified by the operator to the modeltransforming data generating portion 4. In response, the parameter dataextracting portion 42 in the model transforming data generating portion4 extracts parameter data for the area corresponding to the specifyingdata entered from the input portion 2 from the two-dimensional map data(step S4). In the latter case, the parameter data extracting portion 42in the model transforming data generating portion 4 searches for a roadarea conforming with previously set conditions on the two-dimensionalmap data read from the two-dimensional map data storage means 3 andextracts the parameter data in the vicinity of the found road area(e.g., in the area within a 500-m radius) from the two-dimensional mapdata (step S4).

FIG. 5 shows an example of the parameter data extracted from thetwo-dimensional map data in step S4. In FIG. 5, the vertically listednumbers 1 to 23 correspond to 23 roads (hereinafter referred to aslinks). For example, it shows that the link 1 has a length of 20 m andfour lanes, and its link attribute shows that it is a part of anordinary-type road. Further, since bidirectional passage is permitted,it is known that the four lanes include two lanes for one direction andtwo lanes for the opposite direction. It also shows that the link 4 hasa length of 20 m and two lanes, and its link attribute shows that it isan elevated road. Accordingly it is known that information for avertical direction must be provided for the link 4. It shows that thelink 7 has a length of 5 m and one lane, and its link attribute shows aside pass. Further, the link 17 has a length of 5 m and two lanes, andits link attribute shows an underpass (a road running under an elevatedroad). The map parameters shown in FIG. 5 can be visualized as atwo-dimensional map as shown in FIG. 6.

While this embodiment adopts DRMA for a format of the two-dimensionalmap data stored in the two-dimensional map data storage portion 3 asstated above, two-dimensional map data described in another map dataformat may be stored in the two-dimensional map data storage portion 3.When some data is wanting, e.g. information contained in DRMA but not inanother map data format (e.g., information about the number of lanes),or information contained in another map data format but not in DRMA, itwill be separately entered from the input portion 2.

Next, the pattern determining portion 431 analyzes parameter dataextracted by the parameter data extracting portion 42 to determine towhich patterns of intersection configuration previously classified thethree-dimensional configuration of the target road area belongs (stepS5). FIG. 7 shows the details of this subroutine step S5.

Referring to FIG. 7, the branching area road attribute deciding portion4311 checks, first of all, all the roads connecting to the pointrequired to be navigated (e.g., a branching point between a main roadand a side pass) on the basis of the parameter data extracted by theparameter data extracting portion 42 to decide each attribute thereof;elevated road, underpass, or road on the ground (step S51). Second, thebranch type deciding portion 4312 decides the type of the branching onthe basis of the attributes of the connected roads decided by thebranching area road attribute deciding portion 4311 (step S52). Thebranch type may contain, as shown in FIG. 8, case (a) in which a road onthe ground branches out into an elevated road and a side pass, case (b)in which a road on the ground branches out into an underpass and a sidepass, and case (c) in which an elevated road branches out into anelevated road and a side pass. It then decides a three-dimensional mapdisplay model pattern to be used on the basis of the determined type ofthe branching (step S53). This decision may be made by the operator, inwhich case a pattern number is entered into the parameter data analyzingportion 43 from the input portion 2. For the three-dimensional mapdisplay model patterns, for example, the case (a) of a road on theground branching out into an elevated road and a side pass maycorrespond to the three-dimensional map display model pattern shown inFIG. 9, the case (b) of a road on the ground branching out into anunderpass and a side pass may correspond to the three-dimensional mapdisplay model pattern shown in FIG. 10, and the case (c) of an elevatedroad branching out into an elevated road and a side pass may correspondto the three-dimensional map display model pattern shown in FIG. 11.Further, the branch type deciding portion 4312 gives a pattern numbercorresponding to the determined or entered pattern to the pattern modelstorage portion 5 to read out the pattern data corresponding to thedetermined or entered pattern from the pattern model storage portion 5.As stated above, the pattern model storage portion 5 contains patterndata for defining types of parameters required to transform eachthree-dimensional map display model. FIG. 12 shows an example of thepattern data stored in the pattern model storage portion 5. As shown inFIG. 12, the pattern data is prepared as blank table data in whichparameters are to be set.

Referring to the main routine of FIG. 4 again, the parameter dataclassifying portion 432 classifies the two-dimensional parameter dataextracted by the parameter data extracting portion 42 according to theirrespective road functions, on the basis of the pattern determined in thepattern determining portion 431 (step S6). In the data classification,for example, a multi-level intersection may be classified into a roadnot on the ground for a part of the multilevel intersection, a side passto make a right/left turn, and an approach. The road functions may beclassified on the basis of the configuration of intersections in thisway; in another method, a series of roads existing between adjacentbranching points, or between adjacent merging points, or betweenadjacent branching point and merging point, may be classified as a groupof roads having the same function.

FIG. 13 shows an example of the two-dimensional parameter dataclassified according to the road function. The data shown in FIG. 5 areused as the classified data. In FIG. 13, the vertically listed numbers 1to 10 correspond to ten roads differing in function. For example, thelink Nos.1 to 3 are data of the same road function, which are classifiedas the road No.1; similarly, the link Nos.4 and 5 are classified as theroad No.2, link No.6 as road No.3, link Nos.7 and 8 as road No.4, linkNo.9 as road No.5, link Nos.10 to 12 as road No.6, link Nos.13 and 14 asroad No.7, link Nos.15 and 16 as road No.8, link Nos.17 to 19 as roadNo.9, and link Nos.20 to 23 as road No.10.

FIG. 14 shows the greater details of the above-described operation inthe subroutine step S6. Referring to FIG. 14, first, the link tracingportion 4321 traces links in the three-dimensioned area on the basis ofthe parameter data extracted by the parameter data extracting portion 42and temporarily holds the links required to generate a three-dimensionalmap display model (step S61). FIG. 15 shows an example of thetwo-dimensional map, FIG. 16 shows an example of results of the trace oflinks, and FIG. 17 shows an example of results of storage of the data oftraced links. The criterion in tracing links may include an attribute,type, angle, area, and the like. Next, the link data classifying portion4322 classifies the link data held in the link tracing portion 4321according to the road function (step S62). The road function may includean approach to a branching point, elevated road from the branchingpoint, and side pass from the branching point; the link data areclassified into roads having the same function. FIG. 18 shows an exampleof links classified according to the road function.

Referring to the main routine of FIG. 4 again, the data integratingportion 433 integrates the parameter data classified in the parameterdata classifying portion 432 (step S7). The data integration means theoperation of integrating the data classified according to road functioninto one road. This data integrating operation may be achieved by amethod of selecting arbitrary data from the plurality of data classifiedaccording to road function and adopting the data as representative ofthe roads in that part, or a method of calculating an average value ofthe plurality of data classified according to road function and adoptingthe average value as the road in that part.

FIG. 19 shows an example of parameter data created by integrating datafor each road function. The data classified in FIG. 13 are used as theintegrated data. For example, while the parameter data corresponding tothe road No.1 is regarded as a group of three link data in FIG. 13, thethree link data are integrated into one road in FIG. 19. Similarly, thedata classified according to road numbers are integrated into one.

The map parameters shown in FIG. 19 can be visualized as atwo-dimensional map as shown in FIG. 20. Although FIG. 20 istwo-dimensionally represented, it substantially shows an example ofintersection pattern prepared as a three-dimensional map display model.In FIG. 20, the types of hatching applied to the road parts 1 to 10represent the road functions classified in the pattern. Morespecifically, the road parts 2 and 9 belong to a road not on the ground(elevated road or underpass), the road parts 4 to 7 belong to a sidepass, and the road parts 1, 3, 8 and 10 belong to an approach. Theparameters of FIG. 19, which have been generated as the result ofclassification and integration, correspond to the road parts shown inFIG. 20, where the road Nos.1 to 10 in FIG. 19 correspond to the roadparts 1 to 10 in FIG. 20, respectively. When the configuration of theprepared intersection pattern differs from that of FIG. 20, a structureintegrated according to the pattern configuration is changed inparameter data generated as shown in FIG. 19. The parameter dataintegrated in the data integrating portion 433 is given to the dataconverting portion 434 as normalized parameter data.

Next, the data converting portion 434 converts the parameter data givenfrom the data integrating portion 433 into model transforming data onthe basis of the pattern data read out from the pattern model storageportion 5 (step S8). The operation of the data converting portion 434will be described in greater detail below.

Among the parameter data normalized in the normalizing portion 430, thedata converting portion 434 first sets parameter data which can besimply transferred, into the pattern data read out from the patternmodel storage means 6. FIG. 21 shows an example of the pattern data inwhich the parameters are set. Referring to FIG. 21, the data convertingportion 434 sets the parameter showing length and the parameter showingthe number of lanes in the pattern data, as the parameter data which cansimply be transferred. The parameter showing the number of lanes is setas the parameter showing the width of road.

Next, the data converting portion 434 analyzes the parameter datanormalized in the normalizing portion 430 to infer values of other unsetparameters in the pattern data. For example, since the link 2 is anelevated road and the link 9 is an underpass, it infers that the tworoads intersect each other with the link 2 located in the higher level.Accordingly a height flag 1 is set to the link 2 in the pattern data,and a height flag 0 is set to the link 9. A height flag with a largernumber indicates a higher position. When the angle of the intersectionof link 2 and link 9 can be calculated from the normalized parameterdata, the calculated intersecting angle is set in the pattern data.Usually, DRMA shows the coordinate positions of links, and theintersecting angles can be calculated from the coordinate positions. Thedata converting portion 434 also infers the configuration of links andsets the result in the pattern data as the parameter showing theconfiguration pattern. The configurations of links are classified intosome categories. For example, the first category shown in FIG. 22 (acategory showing the shape of ordinary-type roads), the second categoryshown in FIG. 23 (a category showing the shape of elevated roads), andthe third category shown in FIG. 24 (a category showing how the roadsare connected at branching/merging points) are included. At this time,in the simplest method for inferring a shape of ordinary-type roads, theshapes of the roads in the whole country are collected so as to decidewhich shape is the most popular for links of the determined pattern, andthen the most popular shape among the roads is set for a shape of therespective link. It is possible to infer how an elevated road isconfigured, or how roads are connected to one another at abranching/merging point from the relation among interconnected links inthe neighborhood.

Parameters not specified by inference may be left unset, or someparameters may be temporarily set. When parameters are not set, theconfiguration of the links is displayed according to the configurationof a standard three-dimensional map display model buried in thethree-dimensional image data generating algorithm executed by the imagedata generating portion 6. However, there is no problem in thisembodiment because the parameters can be corrected later by theoperator.

Next, the data converting portion 434 outputs the pattern data in whichthe parameters are set to the image data generating portion 6 as modeltransforming data. The image data generating portion 6 generatesthree-dimensional image data on the basis of the model transformingdata, and outputs it to the display 7 (step S9). In response, thedisplay 7 displays a three-dimensional map. The image data generatingportion 6 can achieve the calculation by just transforming a previouslydefined three-dimensional map display model with the model transformingdata, instead of performing all the calculations for generating thethree-dimensional image data. Accordingly the three-dimensional imagedata generating algorithm in the image data generating portion 6 can beconsiderably simplified as compared with the conventional algorithmwhich processes two-dimensional map data with added width and heightinformation as three-dimensional coordinate data to generate thethree-dimensional polygon data. This effect can be obtained similarlyalso in the three-dimensional map display performed later in the carnavigation system carried on a vehicle. The amount of calculation forexecuting the simplified three-dimensional image data generatingalgorithm is greatly reduced, which enables smooth map scrolling. Thedetailed structure and operation of the image data generating portion 6will be described later.

Next, the operator checks the contents displayed in the display 7 to seewhether a correct three-dimensional image is displayed (step S10). Whenthe three-dimensional image should be corrected, parameters for changeor addition are entered from the input portion 2 (step S11). Thischanges the contents of the model transforming data generated in theparameter data analyzing portion 43 and the contents displayed in thedisplay 7 also changes accordingly. When the three-dimensional imagedisplayed in the display 7 has been changed to satisfy the operator, themodel transforming data generated in the parameter data analyzingportion 43 is outputted to and stored in the model transforming datastorage portion 8 (step S12). FIG. 25 shows an example of display of athree-dimensional map corresponding to the model transforming data shownin FIG. 21.

When a large number of areas are specified for three-dimensional displayin step S3 of FIG. 4 in the above embodiment, the model transformingdata can be generated for all roads on the map, and then the carnavigation system can three-dimensionally display all the roads undercar-navigation.

Further, in the present invention, in order to improve the efficiency inthe process of creating model transforming data and the process ofgenerating the three-dimensional image data, and also in order toimprove the quality of the created three-dimensional map data, thethree-dimensional map may be created and displayed according to patternshaving a hierarchical structure called a macro/micro pattern. The macropattern handles a mass of models required in navigation as a singlepattern; for example, FIGS. 9 to 11 show three-dimensional map displaymodels corresponding to the macro patterns of typical multi-levelintersection configurations. For example, FIG. 9 shows a typicalmulti-level intersection model, which is composed of an approach roadreaching a branching point, a side pass, and an elevated road. However,when three-dimensional map display models are created only with themacro pattern models, multi-level intersections not conforming with thepatterns cannot be represented, and the number of patterns increases insteps depending on the number of sampling data for the objectintersections to be three-dimensionally displayed. Moreover, there is aproblem that independently developing different macro patterns reducesexpandability and reusability in the future. Accordingly, for thepurpose of compensating for the disadvantages of the macro pattern andexpanding the three-dimensional display to all roads, the micro patternsystem is used together with it to create the three-dimensional mapdisplay models. The micro pattern means a unit of pattern, such as theroad shape primitive patterns shown in FIG. 22, elevated road shapeprimitive patterns as shown in FIG. 23, and patterns for connectingprimitive patterns as shown in FIG. 24 (branching, merging,intersecting, and the like.); the micro patterns are combined to form athree-dimensional map display model. That is to say, to improve theefficiency in creating the model transforming parameters, and also tonormalize the created model for better appearance, typical multi-levelintersections are three-dimensioned by using macro patterns showingintersection structures hierarchically structured according toexperiential knowledge, and parts not conforming with the structure arethree-dimensionally represented by using the micro patterns. However, adesired three-dimensional map display model can be created merely bycombining micro patterns, without using the macro pattern.

FIG. 26 is a block diagram showing the greater details of the image datagenerating portion 6 shown in FIG. 1. In FIG. 26, the three-dimensionaldata generating portion 6 includes a three-dimensional polygon datagenerating portion 61, a rendering portion 62, a three-dimensionalpolygon data storage portion 63, and a three-dimensional image datastorage portion 64.

The three-dimensional polygon data generating portion 61 generatesthree-dimensional polygon data on the basis of the model transformingdata provided from the model transforming data generating portion 4. Thegenerated three-dimensional polygon data is stored in thethree-dimensional polygon data storage portion 63 and is also providedto the rendering portion 62. The rendering portion 62 generatesthree-dimensional image data on the basis of the three-dimensionalpolygon data generated in the three-dimensional polygon data generatingportion 61. The generated three-dimensional image data is stored in thethree-dimensional image data storage portion 64 and is also provided tothe display 7.

FIG. 27 is a block diagram showing the greater details of thethree-dimensional polygon data generating portion 61 shown in FIG. 26.In FIG. 27, the three-dimensional polygon data generating portion 61includes a model transforming data analyzing portion 611, athree-dimensional polygon data synthesizing portion 612, a configurationattribute storage portion 613, and a three-dimensional polygon library614.

The model transforming data analyzing portion 611 analyzes the parameterdata generated by the model transforming data generating portion 4 foreach road area to select a three-dimensional map display modelcorresponding to the pattern of the road configuration as shown in FIG.23 and to extract parameter values of the road length, road width, andthe like.

The configuration attribute storage portion 613 is used to storeparameters for more finely transforming the road configuration patternmodel corresponding to the three-dimensional map display model, whichcontains parameter values for the color and material of roads, spacingand number of bridge girders attached to elevated roads, width ofshoulders, height of sound-proof walls, and the like, for example.

FIG. 28 shows an example of contents of parameters and their defaultvalues stored in the configuration attribute storage portion 613. InFIG. 28, by way of example, the configuration attribute storage portion613 contains parameters about the spacing between supports (girders) ofelevated road, parameters about safety walls (placement offset, widthand height of safety walls), parameters about traffic lights (the filename of the polygon library containing polygon data about trafficlights, height and scale factor, and type of traffic lights), parametersabout background (the name of the file containing texture materialimages used for background), parameters about the size of thethree-dimensional model world (width, length and thickness of the groundin the three-dimensional model world, coordinate values of the horizon),parameters about the color of roads, parameters about the color ofelevated roads, parameters about the color of safety walls, parametersabout the color of supports, parameters about roads (thickness of roads,width of one lane), and parameters about elevated roads (height, h, ofone level, grade of first section 11, grade of second section 12, gradeof third section 13).

The three-dimensional polygon library 614 contains polygon data foraccessories attached to the three-dimensional map, such as trafficlights and various landmarks (banks, shops, schools, etc.).

The three-dimensional polygon data synthesizing portion 612 createscorresponding three-dimensional polygon data by referring to the dataanalyzed in the model transforming data analyzing portion 611, variousparameters stored in the configuration attribute storage portion 613,and polygon data stored in the three-dimensional polygon library 614.

FIG. 29 is a flowchart showing the operation of the three-dimensionalpolygon data generating portion 61 shown in FIG. 26. Referring to FIG.29, the operation of the three-dimensional polygon data generatingportion 61 will now be described.

First, the model transforming data corresponding to the road area to bethree-dimensionally displayed is inputted from the model transformingdata generating portion 4 into the three-dimensional polygon datagenerating portion 61 (step S101). In response, the model transformingdata analyzing portion 611 analyzes the input model transforming dataand selects a three-dimensional map display model corresponding to suchroad configuration pattern as shown in FIG. 23 and extracts parametervalues about the road length, road width, etc. (step S102). Next, thethree-dimensional polygon data synthesizing portion 612 reads defaultvalues for various parameters stored in the configuration attributestorage portion 613 (refer to FIG. 28) and also reads the polygon datafor traffic lights and landmarks stored in the three-dimensional polygonlibrary 614 (step S103). Then the three-dimensional polygon datasynthesizing portion 612 calculates the three-dimensional coordinates byreferring to the data analyzed in the model transforming data analyzingportion 611, various parameters stored in the configuration attributestorage portion 613, and polygon data stored in the three-dimensionalpolygon library 614, to create three-dimensional polygon data (stepS104). The created three-dimensional polygon data is provided to therendering portion 62.

The operation of the three-dimensional polygon data generating portion61 will now be described with more specific examples.

First, the operation performed when the model transforming data of thelink No.1 in FIG. 21 is provided to the three-dimensional polygon datagenerating portion 61 will be described. As shown in FIG. 30, when themodel transforming data about the link No.1 is provided to the modeltransforming data analyzing portion 611, the model transforming dataanalyzing portion 611 extracts the following parameters from the modeltransforming data:

Link No.=1

Length=50

Width=4

Road shape=1

Elevated road shape=no definition

Connection shape=1a

Height=no definition

Since the extracted parameters do not define the elevated road shape norheight, it is known that the road corresponding to this link is a roadon the ground having no supports for elevated road. At this time, asshown in FIG. 22, since the road shape=1 corresponds to a linear roadshape, the model transforming data analyzing portion 611 selectsfunction FUNC1 for generating a rectangular prism polygon from thewidth, length, and thickness, and sets the parameter values extractedfrom the model transforming data in the selected function FUNC1 (in thiscase, length=50, width=4). The function FUNC1 with the set parametervalues is provided to the three-dimensional polygon data synthesizingportion 612.

Receiving the function FUNC1 from the model transforming data analyzingportion 611, the three-dimensional polygon data synthesizing portion 612reads configuration attribute information required for the functionFUNC1 (in this case, color of road=gray, thickness of road=0.5, width ofroad=3.5) from the configuration attribute information stored in theconfiguration attribute storage portion 613 (see FIG. 28).

The outline of the processing of the function FUNC1 will now bedescribed referring to FIG. 32. FIG. 33 shows an image diagram of thethree-dimensional polygon data generated in the function FUNC1. Thepolygon shown in FIG. 33 has the eight vertexes (a, b, c, d, e, f, g,h). Then the coordinates of the vertexes and the list of vertexesdefining the faces can be represented by the following combinations ofparameters, by calculating with length=l, width=w, and thickness=dep andusing the vertex “a” as the origin:

a=(0, 0, 0)

b=(0, 1, 0)

c=(w, 1, 0)

d=(w, 0, 0)

e=(0, 0, dep)

f=(0, 1, dep)

g=(w, 1, dep)

h=(w, 0, dep)

The structure of the face list can be represented by the followingvertex list:

f1=(a, b, c, d)

f2=(d, c, g, h)

f3=(h, g, f, e)

f4=(e, f, b, a)

f5=(a, d, h, e)

f6=(b, c, g, f)

Then the three-dimensional polygon data synthesizing portion 612 appliesw=14, l=50, and dep=0.5 to the functions to calculate values of thevertexes. The calculation provides the following results:

a=(0, 0, 0)

b=(0, 50, 0)

c=(14, 50, 0)

d=(14, 0, 0)

e=(0, 0, 0.5)

f=(0, 50, 0.5)

g=(14, 50, 0.5)

h=(14, 0, 0.5)

Further, since the road texture=gray, the material is set as (R, G,B)=(0.2, 0.2, 0.2). For the RGB value, the RGB default value defininggray is referred to. The road texture may be defined for each face, orone texture may be defined for one road. The three-dimensional polygondata 1 thus calculated is provided to the rendering portion 62 as thethree-dimensional polygon data 1 as shown in FIG. 32.

Next, the operation performed when the model transforming data of thelink No.4 in FIG. 21 is provided to the three-dimensional polygon datagenerating portion 61 will now be described. As shown in FIG. 30, whenthe model transforming data of link No.4 is provided to the modeltransforming data analyzing portion 611, the model transforming dataanalyzing portion 611 extracts the following parameters from the modeltransforming data:

Link No.=4

Length=10

Width=1

Road shape=1

Elevated road shape=1

Connection shape=1d

Height=no definition

Since the extracted parameters define the shape of elevated road, it isknown that the road corresponding to this link is a road not on theground. At this time, as shown in FIG. 22, since the road shape=1corresponds to the linear road shape, the model transforming dataanalyzing portion 611 selects function FUNCB1 for generating anelevated-road type polygon only from the width, length, and thickness,and sets the parameter values extracted from the model transforming datain the selected function FUNCB1 (in this case, length=10, width=1). Thefunction FUNCB1 with the set parameter values is provided to thethree-dimensional polygon data synthesizing portion 612.

Receiving the function FUNCB1 from the model transforming data analyzingportion 611, the three-dimensional polygon data synthesizing portion 612reads configuration attribute information required for the functionFUNCB1 (in this case, color of road=gray, thickness of road=0.5, widthof road=3.5, h=3, l1=2, l2=6, l3=2) from the configuration attributeinformation stored in the configuration attribute storage portion 613(see FIG. 28).

The outline of the processing of the function FUNCB1 will now bedescribed referring to FIGS. 34 and 35. FIG. 36 shows an image diagramof the three-dimensional polygon data generated in the function FUNCB1.The polygon shown in FIG. 36 has the 16 vertexes (1, 2, 3, 4, 5, 6, 7,8, 9, 10, 11, 12, 13, 14, 15, 16). Then the coordinates of the vertexesand the list of vertexes defining the faces can be represented by thefollowing combinations of parameters, by calculating with length=l,width=w, and thickness=dep, and elevated-road parameter height=h, firstsection grade=l1, second section grade=l2, third section grade=l3, andusing the vertex 1 as the origin:

1=(0, 0, 0)

2=(0, l1, h)

3=(0, l1+l2, h)

4=(0, l, 0)

5=(0, 0, −dep)

6=(0, l1, h−dep)

7=(0, l1+l2, h−dep)

8=(0, l, −dep)

9=(w, 0, 0)

10=(w, l1, h)

11=(w, l1+l2, h)

12=(w, l, 0)

13=(w, 0, −dep)

14=(w, l1, h−dep)

15=(w, l1+l2, h−dep)

16=(w, l, −dep)

The structure of the face list can be represented by the followingvertex list:

f1=(1, 2, 10, 9)

f2=(2, 3, 11, 10)

f3=(3, 4, 12, 11)

f4=(9, 10, 14, 13)

f5=(10, 11, 15, 14)

f6=(11, 12, 16, 15)

f7=(5, 6, 14, 13)

f8=(6, 7, 15, 14)

f9=(7, 8, 16, 15)

f10=(1, 2, 6, 5)

f11=(2, 3, 7, 6)

f12=(3, 4, 8, 7)

f13=(1, 5, 13, 9)

f14=(4, 8, 16, 12)

Then the three-dimensional polygon data synthesizing portion 612 appliesw=3.5, l=10, dep=0.5, l1=2, l2=6, l3=2, h=3 to the functions tocalculate the values of the vertexes. The calculation results asfollows:

1=(0, 0, 0)

2=(0, 2, 3)

3=(0, 4, 3)

4=(0, 10, 0)

5=(0, 0, −0.5)

6=(0, 2, 2.5)

7=(0, 4, 2.5)

8=(0, 10, −0.5)

9=(3.5, 0, 0)

10=(3.5, 2, 3)

11=(3.5, 4, 3)

12=(3.5, 10, 0)

13=(3.5, 0, −0.5)

14=(3.5, 2, 2.5)

15=(3.5, 4, 2.5)

16=(3.5, 10, −0.5)

Further, since the elevated-road texture=gray, the material is set as(R, G, B)=(0.2, 0.2, 0.2). For the RGB value, the RGB default valuedefining gray is referred to. The elevated-road texture may be definedfor each face, or one texture may be defined for one elevated road. Thethree-dimensional polygon data B1 thus calculated is provided to therendering portion 62 as the three-dimensional polygon data B1 as shownin FIG. 35.

The three-dimensional polygon data generating portion 61 repeats theabove-described series of processes for the number of the modeltransforming data. While the three-dimensionally polygon synthesizedcoordinate values are described about the origin to simply describe theflow of processing, the adjustment of the coordinate values isre-calculated on the basis of the connecting configuration pattern andintersecting angle values in the model transforming data.

The model transforming data are created for a plurality of road areas asdescribed above and stored in the model transforming data storageportion 8. After that, preferably, the model transforming data stored inthe model transforming data storage portion 8 are stored in the samestorage medium together with the two-dimensional map data stored in thetwo-dimensional map data storage portion 3. At this time, thecorrespondence between the model transforming data and thetwo-dimensional map data is also described in the storage medium. Thestorage medium is then set in a car navigation system carried on avehicle and used for navigation. That is to say, the car navigationsystem has a three-dimensional image data generating algorithmequivalent to step S9 in FIG. 4, and when the vehicle comes closer to aroad area to be three-dimensionally displayed, the three-dimensionalimage data generating algorithm reads out a model transforming datacorresponding to the road area, gives it to the correspondingthree-dimensional map display model and transforms it, and thusgenerates and displays the desired three-dimensional image data.

The model transforming data obtained in the above-described way can beapplied not only to a navigation system for a vehicle but also to adrive simulator operating on a personal computer and to a portablenavigation system carried by a man.

Although the model transforming data created by the model transformingdata creating device is stored in a storage medium and used in a carnavigation system in the above-described embodiment, three-dimensionalpolygon data stored in the three-dimensional polygon data storageportion 63 or three-dimensional image data stored in thethree-dimensional image data storage portion 64 may be stored in the mapstorage medium in place of the model transforming data and used in thecar navigation system. In this case, the processing load on the carnavigation system is reduced for it does not perform the calculation fortransforming the three-dimensional map display models, but the amount ofdata stored in the map storage medium is increased.

FIG. 37 is a block diagram showing the structure of a navigation systemaccording to an embodiment of the present invention. In FIG. 37, thenavigation system of this embodiment includes an input portion 10, aposition detecting portion 11, a map data storage portion 13, a routeselecting portion 12, a navigating portion 14, and an output portion 15.

The input portion 10 includes a remote controller, a touch sensor, akeyboard, a mouse, and the like, which is used to select functions ofthe navigation system (to change the processed item, change the map,change the hierarchical level, etc.) and also to set a point, select thesearch mode, and the like. The position detecting portion 11 includes aGPS, a car-velocity sensor, an angular velocity sensor, an absolutedirection sensor, and the like, which is used to detect the currentposition of the vehicle. The map data storage portion 13 is composed ofan optical disk (CD, DVD, etc.), a hard disk, a large-capacity memory,and the like, in which the two-dimensional map data is stored. The routeselecting portion 12 reads the map data of an object area from the mapdata storage portion 13, determines the starting point and destinationon the basis of the current position of the vehicle detected by theposition detecting portion 11 and point information entered from theinput portion 10, and selects the smallest cost route from the startingpoint to the destination (the shortest-time route or theshortest-distance route) while considering traffic regulations atintersections and one-way traffic regulations. The navigating portion 14generates information on navigation for directing the vehicle to reachthe destination according to the navigated route selected by the routeselecting portion 12 on the basis of the map data obtained from the mapdata storage portion 13 and the current position of the vehicle detectedby the position detecting portion 11. The navigation performed here maybe realized with map display, with voice, and the like. The outputportion 15 includes a display device (liquid-crystal display, CRTdisplay, etc.), a speaker, etc., which displays information onnavigation generated in the navigating portion 14 and/or outputs it inaudio.

FIG. 38 is a block diagram showing the greater details of the structureof the navigating portion 14 of FIG. 37. In FIG. 38, the navigatingportion 14 includes a three-dimensional map display decision portion141, a two-dimensional map display portion 142, and a three-dimensionalmap display portion 143.

The three-dimensional map display decision portion 141 decides whetherto display a three-dimensional map on the basis of the vehicle positiondata generated in the position detecting portion 11, the route datagenerated in the route selecting portion 12, and the two-dimensional mapdata stored in the map data storage portion 13. After receiving thedecision of not displaying a three-dimensional map from thethree-dimensional map display decision portion 141, the two-dimensionalmap display portion 142 generates two-dimensional map display data onthe basis of the vehicle position data generated in the positiondetecting portion 11, the route data generated in the route selectingportion 12, and the two-dimensional map data stored in the map datastorage portion 13. After receiving the decision of requiring athree-dimensional display from the three-dimensional map displaydecision portion 141, the three-dimensional map display portion 143generates three-dimensional map display data on the basis of the vehicleposition data generated in the position detecting portion 11, the routedata generated in the route selecting portion 12, and thetwo-dimensional map data stored in the map data storage portion 13.

FIG. 39 is a flowchart showing the operation of the navigating portion14 shown in FIG. 37. The operation of the navigating portion 14 will nowbe described referring to FIG. 39.

First, the three-dimensional map display decision portion 141 reads thetwo-dimensional map data about the area corresponding to the currentposition detected in the position detecting portion 11 from the map datastorage portion 13 and searches the read two-dimensional map data for athree-dimensional map display flag (step S301). Next, thethree-dimensional map display decision portion 141 determines whetherthere is a three-dimensional map display flag from the result of thesearch (step S302). When a three-dimensional map display flag is notcontained, the two-dimensional map display portion 142 generates thetwo-dimensional map display data (step S304). When a three-dimensionalmap display flag is contained, the three-dimensional map display portion143 generates the three-dimensional map display data (step S303).

FIG. 40 is a block diagram showing the structure of thethree-dimensional map display portion 143 shown in FIG. 38 in greaterdetail. In FIG. 40, the three-dimensional map display portion 143includes a model transforming data storage portion 1431, athree-dimensional polygon data generating portion 1432, and a renderingportion 1433.

The model transforming data storage portion 1431 is composed of alarge-capacity storage device containing a CD-ROM or DVD as a storagemedium, which contains the model transforming data created by the modeltransforming data creating device 1 shown in FIG. 1. Thethree-dimensional polygon data generating portion 1432 has the samestructure as the three-dimensional polygon data generating portion 61shown in FIG. 26, which generates three-dimensional polygon data on thebasis of the model transforming data stored in the model transformingdata storage portion 1431. That is to say, the three-dimensional polygondata generating portion 1432 reads the model transforming datacorresponding to the road area to be three-dimensionally displayed fromthe model transforming data storage portion 1431 and selects athree-dimensional map display model corresponding to the roadconfiguration pattern and extracts the parameter values about the roadlength, width, and the like. Then the three-dimensional polygon datagenerating portion 1432 sets the default values of parameters about thecolor and material of road, spacing and number of girders attached toelevated road, width of shoulders and height of sound-proof walls, andthe like, and also refers to the three-dimensional polygon library fortraffic lights and landmarks, and calculates the three-dimensionalcoordinates of the three-dimensional polygons to generate thethree-dimensional polygon data. The rendering portion 1433 has the samestructure as the rendering portion 62 shown in FIG. 26, which generatesthree-dimensional image data on the basis of the three-dimensionalpolygon data generated in the three-dimensional polygon data generatingportion 1432. The generated three-dimensional image data is given to theoutput portion 15.

FIG. 41 is a flowchart showing the operation of the three-dimensionalmap display portion 143 shown in FIG. 40. Referring to FIG. 40, theoperation of the three-dimensional map display portion 143 will bedescribed. First, the three-dimensional polygon data generating portion1432 reads model transforming data corresponding to thethree-dimensionally displayed road area from the model transforming datastorage portion 1431 (step S401), and analyzes the parameter data aboutthe road area and selects a three-dimensional map display modelcorresponding to the road configuration pattern, as shown in FIG. 23,and extracts parameter values about the road length, road width, and thelike. (step S402). Next, the three-dimensional polygon data generatingportion 1432 reads the default values of parameters about the color andmaterial of road, spacing and number of girders attached to elevatedroad, width of shoulders and height of sound-proof walls, and the like.,and it also reads polygon data about traffic lights and landmarks storedin the three-dimensional polygon library in the three-dimensionalpolygon data generating portion 1432 (step S403). Then thethree-dimensional polygon data generating portion 1431 calculates thethree-dimensional coordinates of the three-dimensional polygons byreferring to the information and data and thus creates thethree-dimensional polygon data (step S404). Next, the rendering portion1433 performs rendering on the basis of the three-dimensional polygondata created in step S404 to create the three-dimensional image data(step S405). Next, the rendering portion 1433 outputs the createdthree-dimensional image data to the output portion 15 (step S406).

While the model transforming data is fixedly stored in the modeltransforming data storage portion 1431 in the embodiment shown in FIG.40, a communication device 1434 may be added as shown in FIG. 42, inwhich case model transforming data transmitted from a center station(not shown) is received at the communication device 1434 and the modeltransforming data stored in the model transforming data storage portion1431 is updated in a real-time manner.

FIG. 43 is a block diagram showing another structure of thethree-dimensional map display portion 143 shown in FIG. 38. In FIG. 43,the three-dimensional map display portion 143 includes a modeltransforming data generating portion 1435, the three-dimensional polygondata generating portion 1432, and the rendering portion 1433.

The model transforming data generating portion 1431 has the samestructure as the model transforming data generating portion 4 and thepattern model storage portion 5 shown in FIG. 1, which generates modeltransforming data on the basis of the two-dimensional map data stored inthe map data storage portion 13. The three-dimensional polygon datagenerating portion 1432 generates three-dimensional polygon data on thebasis of the model transforming data generated in the model transformingdata generating portion 1431. The rendering portion 1433 performsrendering on the basis of the three-dimensional polygon data created inthe three-dimensional polygon data generating portion 1432 to create thethree-dimensional image data. While the processing load on thenavigation system is increased in this example since the modeltransforming data is generated in the navigation system, the amount ofdata stored inside is considerably reduced since the model transformingdata is not stored in advance.

INDUSTRIAL APPLICABILITY

As described above, the model transforming data generated in the presentinvention can effectively be used when displaying a three-dimensionalmap in a car navigation system, and the like.

What is claimed is:
 1. A method for displaying a three-dimensionalconfiguration of a given part on two-dimensional map data, said methodcomprising: classifying in advance the three-dimensional configurationof the given part into a plurality of patterns and preparing in advancea transformable three-dimensional map display model for each of thepatterns; extracting parameter data corresponding to the given part fromthe two-dimensional map data; generating model transforming data fromthe extracted parameter data; and applying the model transforming datato the corresponding three-dimensional map display model to transformthe three-dimensional map display model into a desired form, andobtaining a three-dimensional image of the given part.